1. Field of the Invention
The present invention relates to an optical pickup module, and more particularly, to an optical pickup module which can be easily assembled and eliminate noise.
2. Description of the Related Art
A disc has various advantages such as great storage capacities, easy maintenance, long lasting preservation, low cost and durability. Accordingly, discs have gradually replaced traditional magnetic storage media, and become one of indispensable optical storage media. Generally speaking, a CD-ROM player or other type CD player is used to read (or reproduce) data stored in a disc. Regardless which type of CD player is used, an optical pickup head moves back and forth along a track-seeking path to read the data stored in the disc. However, the movement of the optical pickup head easily generates noise which makes the user uncomfortable while the data is reproducing.
FIG. 1A is a drawing showing an assembly of the traditional optical pickup module. FIG. 1B is a drawing showing the connection of the first shaft and the fastening plate according to the traditional technology. FIG. 1C is a vertical sectional view showing the traditional first shaft and the fastening plate after assembled. Referring to FIGS. 1A-1C, the traditional optical pickup module 100 comprises a base 110, a first fastening component 120, a first shaft 130, two second fastening components 140, a second shaft 150 and an optical pickup head 160. The optical pickup head 160 reads data stored in a disc (not shown) along the track-seeking path F. The base 110 further comprises a fastening plate 170, and the fastening plate 170 comprises a through hole 172 shown in FIG. 1C.
In addition, the first fastening component 120 and these two second fastening components 140 are disposed on the base 110. One end of the first shaft 130 is inserted in the through hole 172. Another end of the first shaft 130 connects with the first fastening component 120. Two ends of the second shaft 150 are assembled to the base 110 through the two second fastening components 140. Particularly note that the first shaft 130 and the second shaft 150 are assembled to parallel with the track-seeking path F. In addition, the optical pickup head 160 is movably disposed on the first shaft 130 and the second shaft 150 so as to move back and forth along the track-seeking path F.
The traditional fastening plate 170 is disposed on a reference plane R. A normal vector N of the reference plane R is parallel to the track-seeking path F. In order to smoothly assemble one end of the first shaft 130 into the through hole 172 of the fastening plate 170, the inner diameter D2 of the through hole 172 of the fastening plate 170 is slightly larger than the outer diameter D1 of the first shaft 130. Specifically, the inner diameter D2 of the through hole 172 must be at least larger than the outer diameter D1 of one end of the first shaft 130 so that the end of the shaft 130 can be inserted into the through hole 172 at a tilt angle shown in FIG. 1B. Since the inner diameter D2 of the though hole 172 is larger than the outer diameter D1 of the first shaft 130, a gap exists between the first shaft 130 and the through hole 172 of the fastening plate 170 after the first shaft 130 is assembled in the through hole 172. As a result, while the optical pickup head 160 of the optical pickup module 100 moves back and forth along the first shaft 130 and the second shaft 150, the vibration of the first shaft 130 results in noise.